1. Field of the Invention
The present invention generally relates to an LED, in particular, to a packaging method of LED of high heat-conducting efficiency and a structure thereof.
2. Description of Prior Art
Light-emitting diode (LED) is a semiconductor component in solid state, which applies an inter-combination of electron and hole to release energy in a form of light. LED belongs to luminescence lighting and has many merits, such as: small size, long life, low electricity consumption, quick reaction speed, and vibrating endurance. Basically, LED is a light-emitting component for a variety of appliance, information-showing board, and communicating product.
As shown in FIG. 1 and FIG. 2 (i.e. ROC Patent M292879), when a traditional LED is manufactured, a metallic plate 100 is firstly stamped into a lead frame 101, which is placed into a die together with a metallic base 103. After injection formation, two electrode legs 102 of the lead frame 101 and a partial area of the base 103 are enclosed and fixed by the glue seat 104, making base 103 and two electrode legs 102 located in an indentation 105 of the glue seat 104. Next, the light-emitting chip 106 is die-bonded onto the surface of the base 103 by means of silver glue, and the light-emitting chip 106 and two electrode legs 102 are electrically connected by gold wires 107. Finally, after a fluorescent glue body 108 is attached to the light-emitting chip, an epoxy resin 109 is further filled into the indentation 105 of the glue seat 104.
However, the above manufacturing steps of LED are so tedious that they consume too many working time and labor, making it being impossible to lower down the manufacturing cost. According to the prior manufacturing method of LED, a light-emitting chip 106 is firstly pasted onto a base (or lead frame) by means of silver glue, then the positive and negative electrodes of the light-emitting chip 106 are connected to the electrode legs 102 by means of wiring machine with gold or aluminum wire, finally an epoxy resin 109 is applied to complete the packaging procedure. However, since the poor physical characteristics of electrode legs 102, base 103, and epoxy resin 109 in terms of heat conduction, heat resistance reaches as high as 250° C./W˜300° C./W in this traditional packaging form. Therefore, the temperature of LED will rise due to the poor heat dissipation, consequently causing the deterioration and ageing of the epoxy resin 109. In a long term, the light-emitting efficiency of the LED will be decreased and the temperature increment will be accelerated, because of the thermal accumulation. A poor reliability phenomenon is caused by a structure stress generated from the temperature increment.
Accordingly, aiming to solve aforementioned shortcomings, after a substantially devoted study, in cooperation with the application of relatively academic principles, the inventor has at last proposed the present invention that is designed reasonably to possess the capability to improve the prior arts significantly.